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Integrate exponentials of two bases over a power of x to the exponential integral - #1963

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exponentials-of-two-bases-over-a-power-of-x
Oct 20, 2026
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@Rafael-SOWNet Rafael-SOWNet commented Oct 20, 2026 •

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a^x b^x/x was declined. The rules read one exponential, and no spelling of the integrand merges a^x b^x into one: (a b)^x is e^(x ln(a b)), and ln(a b) is not ln(a) + ln(b) for every a and b.

Beside a negative power of x, a product of exponentials whose exponent has no quadratic left is now integrated term by term: each power of x against e^(b x), by parts down to Ei(b x). A rate that cancels, b - b from e^(b x) e^(-b x), is decided by its value and leaves a power of x alone. A first version took that rate as written and divided by it, which gave two wrong answers. Those cases are in the test now.

Measured on 8a1ef454, branch against master:

Run Problems Master Branch
Pocket: Rubi's 2.1–2.3 and 8.1–8.5 1,070 1,021 solved 1,024 solved
Family 1, 40 a file 1,381 1,362 1,362
Family 0, whole 1,814 1,789 1,789
Families 2 to 8, sampled 2,410 2,362 2,359

Re-run alone on both builds, Rubi's 2.3:637–639 (a^x b^x/x to /x^3) go from declined to answered in under 0.3 s. The other three moves time out on both builds. No run had a wrong answer.

ExponentialsOfTwoBasesOverAPowerOfXIntegralTest differentiates the answers back. BREAKING-CHANGES.md has the entry, with the 2.5.0 column measured on v2.5.0.

Part of #233.

🤖 Generated with Claude Code

https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura

…ial integral

a^x b^x/x was declined. The rules read one exponential, and a^x b^x is two of
different bases that no spelling of the integrand merges: (a b)^x is
e^(x ln(a b)), and ln(a b) is not ln(a) + ln(b) for every a and b. Beside a
negative power of x, the product of exponentials with no quadratic left in the
exponent is now integrated term by term: each power of x against e^(b x), by
parts down to Ei(b x). A rate that cancels, b - b from e^(b x) e^(-b x), is
decided by its value, and leaves a power of x alone. Rubi's 2.3 a^x b^x/x to
a^x b^x/x^3.

Part of #233.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
@Rafael-SOWNet Rafael-SOWNet added this to the 2.6.0 milestone Oct 20, 2026
@Rafael-SOWNet
Rafael-SOWNet merged commit 58d0dec into master Oct 20, 2026
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@github-project-automation github-project-automation Bot moved this from Todo to Done in AngouriMath Oct 20, 2026
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